resolvers

package
v3.4.8 Latest Latest
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 Go to latest Published: Dec 2, 2019 License: Apache-2.0 Imports: 19 Imported by: 0

Documentation

Index

Constants

View Source 
const (
	PriorityLow int = iota
	PriorityHigh
	PriorityCritical
)

The priority levels for DNS resolution.

View Source 
const (
	QueryAttempts  = 64
	QueryTimeout   = 65
	QueryRTT       = 66
	QueryCompleted = 67
)

Index values into the Resolver.Stats map.

View Source 
const (
	// CurrentScore is an index value into the ScoredResolver.Stats map.
	CurrentScore = 128

	// PassingScore is the minimum score required to continue use of the Resolver.
	PassingScore = 50
)
View Source 
const (
	MaxDNSNameLen  = 253
	MaxDNSLabelLen = 63
	MinLabelLen    = 6
	MaxLabelLen    = 24
	LDHChars       = "abcdefghijklmnopqrstuvwxyz0123456789-"
)

Constants related to DNS labels.

View Source 
const (
	WildcardTypeNone = iota
	WildcardTypeStatic
	WildcardTypeDynamic
)

Names for the different types of wildcards that can be detected.

View Source 
const (
	// CurrentRate is an index value into the RateLimitedResolver.Stats map
	CurrentRate = 256
)
View Source 
const NotAvailableRcode = 256

NotAvailableRcode is our made up rcode to indicate an availability problem.

Variables

This section is empty.

Functions

func NsecTraversal 

func NsecTraversal(domain, server string) ([]*requests.DNSRequest, error)

NsecTraversal attempts to retrieve a DNS zone using NSEC-walking.

func RemoveLastDot 

func RemoveLastDot(name string) string

RemoveLastDot removes the '.' at the end of the provided FQDN.

func UnlikelyName 

func UnlikelyName(sub string) string

UnlikelyName takes a subdomain name and returns an unlikely DNS name within that subdomain.

func ZoneTransfer 

func ZoneTransfer(sub, domain, server string) ([]*requests.DNSRequest, error)

ZoneTransfer attempts a DNS zone transfer using the server identified in the parameters. The returned slice contains all the records discovered from the zone transfer.

Types

type BaseResolver 

type BaseResolver struct {
	sync.RWMutex
	Done           chan struct{}
	WindowDuration time.Duration
	CurrentConn    net.Conn
	LastConn       net.Conn
	// contains filtered or unexported fields
}

BaseResolver performs DNS queries on a single resolver at high-performance.

func NewBaseResolver 

func NewBaseResolver(addr string) *BaseResolver

NewBaseResolver initializes a Resolver that send DNS queries to the provided IP address.

func (*BaseResolver) Address 

func (r *BaseResolver) Address() string

Address implements the Resolver interface.

func (*BaseResolver) Available 

func (r *BaseResolver) Available() (bool, error)

Available always returns true.

func (*BaseResolver) GetWildcardType 

func (r *BaseResolver) GetWildcardType(ctx context.Context, req *requests.DNSRequest) int

GetWildcardType returns the DNS wildcard type for the provided subdomain name.

func (*BaseResolver) IsStopped 

func (r *BaseResolver) IsStopped() bool

IsStopped implements the Resolver interface.

func (*BaseResolver) MatchesWildcard 

func (r *BaseResolver) MatchesWildcard(ctx context.Context, req *requests.DNSRequest) bool

MatchesWildcard returns true if the request provided resolved to a DNS wildcard.

func (*BaseResolver) Port 

func (r *BaseResolver) Port() int

Port implements the Resolver interface.

func (*BaseResolver) ReportError 

func (r *BaseResolver) ReportError()

ReportError indicates to the Resolver that it delivered an erroneos response.

func (*BaseResolver) Resolve 

func (r *BaseResolver) Resolve(ctx context.Context, name, qtype string, priority int) ([]requests.DNSAnswer, bool, error)

Resolve performs DNS queries using the Resolver.

func (*BaseResolver) Reverse 

func (r *BaseResolver) Reverse(ctx context.Context, addr string, priority int) (string, string, error)

Reverse is performs reverse DNS queries using the Resolver.

func (*BaseResolver) Stats 

func (r *BaseResolver) Stats() map[int]int64

Stats returns performance counters.

func (*BaseResolver) Stop 

func (r *BaseResolver) Stop() error

Stop causes the Resolver to stop sending DNS queries and closes the network connection.

func (*BaseResolver) SubdomainToDomain 

func (r *BaseResolver) SubdomainToDomain(name string) string

SubdomainToDomain returns the first subdomain name of the provided parameter that responds to a DNS query for the NS record type.

func (*BaseResolver) WipeStats 

func (r *BaseResolver) WipeStats()

WipeStats clears the performance counters.

type RateMonitoredResolver 

type RateMonitoredResolver struct {
	sync.RWMutex
	Done chan struct{}
	// contains filtered or unexported fields
}

RateMonitoredResolver performs DNS queries on a single resolver at the rate it can handle.

func NewRateMonitoredResolver 

func NewRateMonitoredResolver(res Resolver) *RateMonitoredResolver

NewRateMonitoredResolver initializes a Resolver that scores the performance of the DNS server.

func (*RateMonitoredResolver) Address 

func (r *RateMonitoredResolver) Address() string

Address implements the Resolver interface.

func (*RateMonitoredResolver) Available 

func (r *RateMonitoredResolver) Available() (bool, error)

Available returns true if the Resolver can handle another DNS request.

func (*RateMonitoredResolver) GetWildcardType 

func (r *RateMonitoredResolver) GetWildcardType(ctx context.Context, req *requests.DNSRequest) int

GetWildcardType returns the DNS wildcard type for the provided subdomain name.

func (*RateMonitoredResolver) IsStopped 

func (r *RateMonitoredResolver) IsStopped() bool

IsStopped implements the Resolver interface.

func (*RateMonitoredResolver) MatchesWildcard 

func (r *RateMonitoredResolver) MatchesWildcard(ctx context.Context, req *requests.DNSRequest) bool

MatchesWildcard returns true if the request provided resolved to a DNS wildcard.

func (*RateMonitoredResolver) Port 

func (r *RateMonitoredResolver) Port() int

Port implements the Resolver interface.

func (*RateMonitoredResolver) ReportError 

func (r *RateMonitoredResolver) ReportError()

ReportError indicates to the Resolver that it delivered an erroneos response.

func (*RateMonitoredResolver) Resolve 

func (r *RateMonitoredResolver) Resolve(ctx context.Context, name, qtype string, priority int) ([]requests.DNSAnswer, bool, error)

Resolve implements the Resolver interface.

func (*RateMonitoredResolver) Reverse 

func (r *RateMonitoredResolver) Reverse(ctx context.Context, addr string, priority int) (string, string, error)

Reverse implements the Resolver interface.

func (*RateMonitoredResolver) Stats 

func (r *RateMonitoredResolver) Stats() map[int]int64

Stats returns performance counters.

func (*RateMonitoredResolver) Stop 

func (r *RateMonitoredResolver) Stop() error

Stop causes the Resolver to stop.

func (*RateMonitoredResolver) SubdomainToDomain 

func (r *RateMonitoredResolver) SubdomainToDomain(name string) string

SubdomainToDomain returns the first subdomain name of the provided parameter that responds to a DNS query for the NS record type.

func (*RateMonitoredResolver) WipeStats 

func (r *RateMonitoredResolver) WipeStats()

WipeStats clears the performance counters.

type ResolveError 

type ResolveError struct {
	Err   string
	Rcode int
}

ResolveError contains the Rcode returned during the DNS query.

func (*ResolveError) Error 

func (e *ResolveError) Error() string

type Resolver 

type Resolver interface {
	// Address returns the IP address where the resolver is located
	Address() string

	// Port returns the port number used to communicate with the resolver
	Port() int

	// Resolve performs DNS queries using the Resolver
	Resolve(ctx context.Context, name, qtype string, priority int) ([]requests.DNSAnswer, bool, error)

	// Reverse is performs reverse DNS queries using the Resolver
	Reverse(ctx context.Context, addr string, priority int) (string, string, error)

	// Available returns true if the Resolver can handle another DNS request
	Available() (bool, error)

	// Stats returns performance counters
	Stats() map[int]int64
	WipeStats()

	// ReportError indicates to the Resolver that it delivered an erroneos response
	ReportError()

	// MatchesWildcard returns true if the request provided resolved to a DNS wildcard
	MatchesWildcard(ctx context.Context, req *requests.DNSRequest) bool

	// GetWildcardType returns the DNS wildcard type for the provided subdomain name
	GetWildcardType(ctx context.Context, req *requests.DNSRequest) int

	// SubdomainToDomain returns the first subdomain name of the provided
	// parameter that responds to a DNS query for the NS record type
	SubdomainToDomain(name string) string

	// Stop the Resolver
	Stop() error
	IsStopped() bool
}

Resolver is the object type for performing DNS resolutions.

type ResolverPool 

type ResolverPool struct {
	Resolvers []Resolver
	Done      chan struct{}
	// Logger for error messages
	Log *log.Logger
	// contains filtered or unexported fields
}

ResolverPool manages many DNS resolvers for high-performance use, such as brute forcing attacks.

func NewResolverPool 

func NewResolverPool(res []Resolver, logger *log.Logger) *ResolverPool

NewResolverPool initializes a ResolverPool that uses the provided Resolvers.

func SetupResolverPool 

func SetupResolverPool(addrs []string, scoring, ratemon bool, log *log.Logger) *ResolverPool

SetupResolverPool initializes a ResolverPool with the type of resolvers indicated by the parameters.

func (*ResolverPool) Address 

func (rp *ResolverPool) Address() string

Address implements the Resolver interface.

func (*ResolverPool) Available 

func (rp *ResolverPool) Available() (bool, error)

Available returns true if the Resolver can handle another DNS request.

func (*ResolverPool) GetWildcardType 

func (rp *ResolverPool) GetWildcardType(ctx context.Context, req *requests.DNSRequest) int

GetWildcardType returns the DNS wildcard type for the provided subdomain name.

func (*ResolverPool) IsStopped 

func (rp *ResolverPool) IsStopped() bool

IsStopped implements the Resolver interface.

func (*ResolverPool) MatchesWildcard 

func (rp *ResolverPool) MatchesWildcard(ctx context.Context, req *requests.DNSRequest) bool

MatchesWildcard returns true if the request provided resolved to a DNS wildcard.

func (*ResolverPool) NextResolver 

func (rp *ResolverPool) NextResolver() Resolver

NextResolver returns a randomly selected Resolver from the pool that has availability.

func (*ResolverPool) Port 

func (rp *ResolverPool) Port() int

Port implements the Resolver interface.

func (*ResolverPool) ReportError 

func (rp *ResolverPool) ReportError()

ReportError implements the Resolver interface.

func (*ResolverPool) Resolve 

func (rp *ResolverPool) Resolve(ctx context.Context, name, qtype string, priority int) ([]requests.DNSAnswer, bool, error)

Resolve performs a DNS request using available Resolvers in the pool.

func (*ResolverPool) Reverse 

func (rp *ResolverPool) Reverse(ctx context.Context, addr string, priority int) (string, string, error)

Reverse is performs reverse DNS queries using available Resolvers in the pool.

func (*ResolverPool) SanityChecks 

func (rp *ResolverPool) SanityChecks()

SanityChecks performs some basic checks to see if the resolvers are reliable.

func (*ResolverPool) Stats 

func (rp *ResolverPool) Stats() map[int]int64

Stats returns performance counters.

func (*ResolverPool) Stop 

func (rp *ResolverPool) Stop() error

Stop calls the Stop method for each Resolver object in the pool.

func (*ResolverPool) SubdomainToDomain 

func (rp *ResolverPool) SubdomainToDomain(name string) string

SubdomainToDomain returns the first subdomain name of the provided parameter that responds to a DNS query for the NS record type.

func (*ResolverPool) WipeStats 

func (rp *ResolverPool) WipeStats()

WipeStats clears the performance counters.

type ScoredResolver 

type ScoredResolver struct {
	sync.RWMutex
	// contains filtered or unexported fields
}

ScoredResolver performs DNS queries on a single resolver and maintains a performance score.

func NewScoredResolver 

func NewScoredResolver(res Resolver) *ScoredResolver

NewScoredResolver initializes a Resolver that scores the performance of the DNS server.

func (*ScoredResolver) Address 

func (r *ScoredResolver) Address() string

Address implements the Resolver interface.

func (*ScoredResolver) Available 

func (r *ScoredResolver) Available() (bool, error)

Available returns true if the Resolver can handle another DNS request.

func (*ScoredResolver) GetWildcardType 

func (r *ScoredResolver) GetWildcardType(ctx context.Context, req *requests.DNSRequest) int

GetWildcardType returns the DNS wildcard type for the provided subdomain name.

func (*ScoredResolver) IsStopped 

func (r *ScoredResolver) IsStopped() bool

IsStopped implements the Resolver interface.

func (*ScoredResolver) MatchesWildcard 

func (r *ScoredResolver) MatchesWildcard(ctx context.Context, req *requests.DNSRequest) bool

MatchesWildcard returns true if the request provided resolved to a DNS wildcard.

func (*ScoredResolver) Port 

func (r *ScoredResolver) Port() int

Port implements the Resolver interface.

func (*ScoredResolver) ReportError 

func (r *ScoredResolver) ReportError()

ReportError indicates to the Resolver that it delivered an erroneos response.

func (*ScoredResolver) Resolve 

func (r *ScoredResolver) Resolve(ctx context.Context, name, qtype string, priority int) ([]requests.DNSAnswer, bool, error)

Resolve implements the Resolver interface.

func (*ScoredResolver) Reverse 

func (r *ScoredResolver) Reverse(ctx context.Context, addr string, priority int) (string, string, error)

Reverse implements the Resolver interface.

func (*ScoredResolver) Stats 

func (r *ScoredResolver) Stats() map[int]int64

Stats returns performance counters.

func (*ScoredResolver) Stop 

func (r *ScoredResolver) Stop() error

Stop causes the Resolver to stop.

func (*ScoredResolver) SubdomainToDomain 

func (r *ScoredResolver) SubdomainToDomain(name string) string

SubdomainToDomain returns the first subdomain name of the provided parameter that responds to a DNS query for the NS record type.

func (*ScoredResolver) WipeStats 

func (r *ScoredResolver) WipeStats()

WipeStats clears the performance counters.

Source Files

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